The influence of the subsurface cisterna on the electrical properties of the outer hair cell

A distributed-parameter computational model of the outer hair cell was used to predict the potentials resulting from current injection. A good fit was found to the length-dependent whole cell conductance and capacitance. The fit required the presence of the subsurface cisterna and a low (0.001 mS/cm2) specific conductivity for the plasma membrane of the lateral wall. The lateral wall could not be space clamped as significant longitudinal currents pass through the extracisternal space vs the axial core. A reduction in the width of the extracisternal space decreased the whole-cell conductance and capacitance. Position-dependent phase shifts were noted during injection of sinusoidal currents (0.001575 rad/micron). These predictions support a role for extracisternal longitudinal potential gradients in experimentally observed non-linear capacitance and electromotility.